Semiconductor fabrication may comprise exposure of a semiconductor substrate to one or more etchants to remove materials from the substrate, followed by rinsing of the substrate to remove the etchants.
Problems may occur during the rinsing if an etchant is not rapidly quenched, in that over-etching may occur. In some applications, the etchant may be sufficiently rapidly quenched by simply flushing deionized water across a wafer to remove the etchant. In other applications, flushing with deionized water alone may not be sufficient to quench an etchant with desired rapidity. For instance, if a semiconductor substrate comprises a topography with deep openings (for instance, openings with high aspect ratios that may be utilized for forming capacitors for DRAM), etchant may remain in the bottoms of high aspect ratio features during a rinse, and continue to etch during the rinse.
One method for increasing the rapidity with which etchant is quenched at the bottoms of openings is to include a quench-inducing composition within a rinsing solution. For instance, if the etchant is an acid, a base may be included within the rinsing solution to assist in quenching the acid. Alternatively, if the etchant is a base, an acid may be included in the rinsing solution. Further, hydrogen peroxide and/or hydrogen chloride may be included in a rinsing solution as a quench-inducing composition.
Problems may occur, however, in utilizing quench-inducing compositions, in that such compositions may themselves be etchants for some materials that are along a semiconductor substrate surface. Accordingly, the utilization of the quench-inducing compositions may alleviate some problems, and yet induce other problems that occur from over-etching caused by the quench-inducing compositions.
It is desirable to develop methods which alleviate or prevent the above-discussed over-etching problems.
Other problems that may occur during semiconductor processing are that particles may form across a semiconductor substrate. Various methods have been developed for removing such particles, but yet problems associated with the particles persist. Accordingly, it is desired to develop new approaches for removing particles from semiconductor substrates.